290 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



basal sandstones and fine conglomerates, of deposits of very fine-grained 

 sandstones and mud rocks.^ 



Absence of marine life in the Algonkian sedimentary rocks. — The 

 almost total absence of a definite marine life in the unmetamorphosed 

 limestones, shales, and sandstones of the Belt formations and all 

 Algonkian formations does not apparently appeal to Rothpletz. With 

 every physical condition favorable to the presence and flourishing 

 existence of an abundant marine fauna there has not been in 30 years 

 examination of these formations by many keen-eyed geologists and 

 paleontologists an authentic reported find of a fauna unmistakably 

 marine and allied to the Cambrian faunas. I reported a transient 

 modified marine fauna from the Grayson shales ' and traces of life 

 in the Grand Canyon series." Later, I recorded algal remains * and 

 bacteria ° from the Newland limestone of the Belt formations, but 

 all of these seem to indicate fresh or brackish water life or a frag- 

 ment of a marine fauna adjusted to fresh-water conditions. This 

 taken in conjunction with the character of the Algonkian sedimenta- 

 tion seems to point to a non-marine epicontinental origin for the 

 known Algonkian formations." 



Further, when speaking of " Pre-Cambrian Continental Condi- 

 tions," I said : ' 



The North American continent was larger at the beginning of known 

 Cambrian time than at any subsequent period other than possibly at the end of 

 the Paleozoic and the end of the Cretaceous, when the land was equally 

 extensive. Indeed, it is highly probable that its area was greater then than 

 even now, for no marine deposits containing pre-Cambrian life, as they were 

 laid down in Lipalian ' time immediately preceding the Cambrian period, have 

 been discovered on the North American continent or elsewhere so far as 

 known. 



^ Darton has described coarse conglomerates at the base of the Cambrian of 

 the Black Hills, South Dakota, but this is in an early Upper Cambrian forma- 

 tion and far east from the Cordilleran region. It seems to be a local deposit. 

 (Prof. Paper, U. S. Geol. Surv., No. 65, 1909, pp. 12, 13.) 



" Bull. Geol. Soc. America, Vol. 10, 1899, pp. 235-238. 



* Idem, p. 232. 



^ Smithsonian Misc. Coll., Vol. 64, No. 2, 1914. 



' Proc. Nat. Acad. Sci., Vol. i, p. 256. 1915. 



^Problems of American Geology. Yale Univ. Press, 1914, Chap. 4: The 

 Cambrian and its Problems, pp. 164-167. 



' Problems of American Geology, Yale Univ. Press. 1914, ®fep. 4 : The 

 Cambrian and its Problems, pp. 166-167. 



* Smithsonian Misc. Coll., Vol. 57, 1910, p. 14 (footnote). 



Lipalian (\ei7ra-|-a-Xs) was proposed for the era of unknown marine sedi- 

 mentation between the adjustment of pelagic life to littoral conditions and the 

 appearance of the Lower Cambrian fauna. It represents the period between 

 the formation (beginning) of the Algonkian continents and the earliest en- 

 croachment of the Lower Cambrian sea. 



